Viewing file:  usb-skeleton.c (17.01 KB) -rw-r--r--
Select action/file-type:
 (+) |  (+) |  (+) | Code (+) | Session (+) |  (+) | SDB (+) |  (+) |  (+) |  (+) |  (+) |  (+) |
/*
* USB Skeleton driver - 0.6
*
* Copyright (c) 2001 Greg Kroah-Hartman (greg@kroah.com)
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License as
* published by the Free Software Foundation; either version 2 of
* the License, or (at your option) any later version.
*
*
* This driver is to be used as a skeleton driver to be able to create a
* USB driver quickly. The design of it is based on the usb-serial and
* dc2xx drivers.
*
* Thanks to Oliver Neukum and David Brownell for their help in debugging
* this driver.
*
* TODO:
* - fix urb->status race condition in write sequence
* - move minor_table to a dynamic list.
*
* History:
*
* 2001_11_05 - 0.6 - fix minor locking problem in skel_disconnect.
* Thanks to Pete Zaitcev for the fix.
* 2001_09_04 - 0.5 - fix devfs bug in skel_disconnect. Thanks to wim delvaux
* 2001_08_21 - 0.4 - more small bug fixes.
* 2001_05_29 - 0.3 - more bug fixes based on review from linux-usb-devel
* 2001_05_24 - 0.2 - bug fixes based on review from linux-usb-devel people
* 2001_05_01 - 0.1 - first version
*
*/
#include <linux/config.h>
#include <linux/kernel.h>
#include <linux/sched.h>
#include <linux/signal.h>
#include <linux/errno.h>
#include <linux/poll.h>
#include <linux/init.h>
#include <linux/slab.h>
#include <linux/fcntl.h>
#include <linux/module.h>
#include <linux/spinlock.h>
#include <linux/list.h>
#include <linux/smp_lock.h>
#include <linux/devfs_fs_kernel.h>
#include <linux/usb.h>
#ifdef CONFIG_USB_DEBUG
static int debug = 1;
#else
static int debug;
#endif
/* Use our own dbg macro */
#undef dbg
#define dbg(format, arg...) do { if (debug) printk(KERN_DEBUG __FILE__ ": " format "\n" , ## arg); } while (0)
/* Version Information */
#define DRIVER_VERSION "v0.4"
#define DRIVER_AUTHOR "Greg Kroah-Hartman, greg@kroah.com"
#define DRIVER_DESC "USB Skeleton Driver"
/* Module paramaters */
MODULE_PARM(debug, "i");
MODULE_PARM_DESC(debug, "Debug enabled or not");
/* Define these values to match your device */
#define USB_SKEL_VENDOR_ID 0xfff0
#define USB_SKEL_PRODUCT_ID 0xfff0
/* table of devices that work with this driver */
static struct usb_device_id skel_table [] = {
{ USB_DEVICE(USB_SKEL_VENDOR_ID, USB_SKEL_PRODUCT_ID) },
{ } /* Terminating entry */
};
MODULE_DEVICE_TABLE (usb, skel_table);
/* Get a minor range for your devices from the usb maintainer */
#define USB_SKEL_MINOR_BASE 200
/* we can have up to this number of device plugged in at once */
#define MAX_DEVICES 16
/* Structure to hold all of our device specific stuff */
struct usb_skel {
struct usb_device * udev; /* save off the usb device pointer */
struct usb_interface * interface; /* the interface for this device */
devfs_handle_t devfs; /* devfs device node */
unsigned char minor; /* the starting minor number for this device */
unsigned char num_ports; /* the number of ports this device has */
char num_interrupt_in; /* number of interrupt in endpoints we have */
char num_bulk_in; /* number of bulk in endpoints we have */
char num_bulk_out; /* number of bulk out endpoints we have */
unsigned char * bulk_in_buffer; /* the buffer to receive data */
int bulk_in_size; /* the size of the receive buffer */
__u8 bulk_in_endpointAddr; /* the address of the bulk in endpoint */
unsigned char * bulk_out_buffer; /* the buffer to send data */
int bulk_out_size; /* the size of the send buffer */
struct urb * write_urb; /* the urb used to send data */
__u8 bulk_out_endpointAddr; /* the address of the bulk out endpoint */
struct tq_struct tqueue; /* task queue for line discipline waking up */
int open_count; /* number of times this port has been opened */
struct semaphore sem; /* locks this structure */
};
/* the global usb devfs handle */
extern devfs_handle_t usb_devfs_handle;
/* local function prototypes */
static ssize_t skel_read (struct file *file, char *buffer, size_t count, loff_t *ppos);
static ssize_t skel_write (struct file *file, const char *buffer, size_t count, loff_t *ppos);
static int skel_ioctl (struct inode *inode, struct file *file, unsigned int cmd, unsigned long arg);
static int skel_open (struct inode *inode, struct file *file);
static int skel_release (struct inode *inode, struct file *file);
static void * skel_probe (struct usb_device *dev, unsigned int ifnum, const struct usb_device_id *id);
static void skel_disconnect (struct usb_device *dev, void *ptr);
static void skel_write_bulk_callback (struct urb *urb);
/* array of pointers to our devices that are currently connected */
static struct usb_skel *minor_table[MAX_DEVICES];
/* lock to protect the minor_table structure */
static DECLARE_MUTEX (minor_table_mutex);
/*
* File operations needed when we register this driver.
* This assumes that this driver NEEDS file operations,
* of course, which means that the driver is expected
* to have a node in the /dev directory. If the USB
* device were for a network interface then the driver
* would use "struct net_driver" instead, and a serial
* device would use "struct tty_driver".
*/
static struct file_operations skel_fops = {
/*
* The owner field is part of the module-locking
* mechanism. The idea is that the kernel knows
* which module to increment the use-counter of
* BEFORE it calls the device's open() function.
* This also means that the kernel can decrement
* the use-counter again before calling release()
* or should the open() function fail.
*
* Not all device structures have an "owner" field
* yet. "struct file_operations" and "struct net_device"
* do, while "struct tty_driver" does not. If the struct
* has an "owner" field, then initialize it to the value
* THIS_MODULE and the kernel will handle all module
* locking for you automatically. Otherwise, you must
* increment the use-counter in the open() function
* and decrement it again in the release() function
* yourself.
*/
owner: THIS_MODULE,
read: skel_read,
write: skel_write,
ioctl: skel_ioctl,
open: skel_open,
release: skel_release,
};
/* usb specific object needed to register this driver with the usb subsystem */
static struct usb_driver skel_driver = {
name: "skeleton",
probe: skel_probe,
disconnect: skel_disconnect,
fops: &skel_fops,
minor: USB_SKEL_MINOR_BASE,
id_table: skel_table,
};
/**
* usb_skel_debug_data
*/
static inline void usb_skel_debug_data (const char *function, int size, const unsigned char *data)
{
int i;
if (!debug)
return;
printk (KERN_DEBUG __FILE__": %s - length = %d, data = ",
function, size);
for (i = 0; i < size; ++i) {
printk ("%.2x ", data[i]);
}
printk ("\n");
}
/**
* skel_delete
*/
static inline void skel_delete (struct usb_skel *dev)
{
minor_table[dev->minor] = NULL;
if (dev->bulk_in_buffer != NULL)
kfree (dev->bulk_in_buffer);
if (dev->bulk_out_buffer != NULL)
kfree (dev->bulk_out_buffer);
if (dev->write_urb != NULL)
usb_free_urb (dev->write_urb);
kfree (dev);
}
/**
* skel_open
*/
static int skel_open (struct inode *inode, struct file *file)
{
struct usb_skel *dev = NULL;
int subminor;
int retval = 0;
dbg(__FUNCTION__);
subminor = MINOR (inode->i_rdev) - USB_SKEL_MINOR_BASE;
if ((subminor < 0) ||
(subminor >= MAX_DEVICES)) {
return -ENODEV;
}
/* Increment our usage count for the module.
* This is redundant here, because "struct file_operations"
* has an "owner" field. This line is included here soley as
* a reference for drivers using lesser structures... ;-)
*/
MOD_INC_USE_COUNT;
/* lock our minor table and get our local data for this minor */
down (&minor_table_mutex);
dev = minor_table[subminor];
if (dev == NULL) {
up (&minor_table_mutex);
MOD_DEC_USE_COUNT;
return -ENODEV;
}
/* lock this device */
down (&dev->sem);
/* unlock the minor table */
up (&minor_table_mutex);
/* increment our usage count for the driver */
++dev->open_count;
/* save our object in the file's private structure */
file->private_data = dev;
/* unlock this device */
up (&dev->sem);
return retval;
}
/**
* skel_release
*/
static int skel_release (struct inode *inode, struct file *file)
{
struct usb_skel *dev;
int retval = 0;
dev = (struct usb_skel *)file->private_data;
if (dev == NULL) {
dbg (__FUNCTION__ " - object is NULL");
return -ENODEV;
}
dbg(__FUNCTION__ " - minor %d", dev->minor);
/* lock our minor table */
down (&minor_table_mutex);
/* lock our device */
down (&dev->sem);
if (dev->open_count <= 0) {
dbg (__FUNCTION__ " - device not opened");
retval = -ENODEV;
goto exit_not_opened;
}
if (dev->udev == NULL) {
/* the device was unplugged before the file was released */
up (&dev->sem);
skel_delete (dev);
up (&minor_table_mutex);
MOD_DEC_USE_COUNT;
return 0;
}
/* decrement our usage count for the device */
--dev->open_count;
if (dev->open_count <= 0) {
/* shutdown any bulk writes that might be going on */
usb_unlink_urb (dev->write_urb);
dev->open_count = 0;
}
/* decrement our usage count for the module */
MOD_DEC_USE_COUNT;
exit_not_opened:
up (&dev->sem);
up (&minor_table_mutex);
return retval;
}
/**
* skel_read
*/
static ssize_t skel_read (struct file *file, char *buffer, size_t count, loff_t *ppos)
{
struct usb_skel *dev;
int retval = 0;
dev = (struct usb_skel *)file->private_data;
dbg(__FUNCTION__ " - minor %d, count = %d", dev->minor, count);
/* lock this object */
down (&dev->sem);
/* verify that the device wasn't unplugged */
if (dev->udev == NULL) {
up (&dev->sem);
return -ENODEV;
}
/* do an immediate bulk read to get data from the device */
retval = usb_bulk_msg (dev->udev,
usb_rcvbulkpipe (dev->udev,
dev->bulk_in_endpointAddr),
dev->bulk_in_buffer, dev->bulk_in_size,
&count, HZ*10);
/* if the read was successful, copy the data to userspace */
if (!retval) {
if (copy_to_user (buffer, dev->bulk_in_buffer, count))
retval = -EFAULT;
else
retval = count;
}
/* unlock the device */
up (&dev->sem);
return retval;
}
/**
* skel_write
*/
static ssize_t skel_write (struct file *file, const char *buffer, size_t count, loff_t *ppos)
{
struct usb_skel *dev;
ssize_t bytes_written = 0;
int retval = 0;
dev = (struct usb_skel *)file->private_data;
dbg(__FUNCTION__ " - minor %d, count = %d", dev->minor, count);
/* lock this object */
down (&dev->sem);
/* verify that the device wasn't unplugged */
if (dev->udev == NULL) {
retval = -ENODEV;
goto exit;
}
/* verify that we actually have some data to write */
if (count == 0) {
dbg(__FUNCTION__ " - write request of 0 bytes");
goto exit;
}
/* see if we are already in the middle of a write */
if (dev->write_urb->status == -EINPROGRESS) {
dbg (__FUNCTION__ " - already writing");
goto exit;
}
/* we can only write as much as 1 urb will hold */
bytes_written = (count > dev->bulk_out_size) ?
dev->bulk_out_size : count;
/* copy the data from userspace into our urb */
if (copy_from_user(dev->write_urb->transfer_buffer, buffer,
bytes_written)) {
retval = -EFAULT;
goto exit;
}
usb_skel_debug_data (__FUNCTION__, bytes_written,
dev->write_urb->transfer_buffer);
/* set up our urb */
FILL_BULK_URB(dev->write_urb, dev->udev,
usb_sndbulkpipe(dev->udev, dev->bulk_out_endpointAddr),
dev->write_urb->transfer_buffer, bytes_written,
skel_write_bulk_callback, dev);
/* send the data out the bulk port */
retval = usb_submit_urb(dev->write_urb);
if (retval) {
err(__FUNCTION__ " - failed submitting write urb, error %d",
retval);
} else {
retval = bytes_written;
}
exit:
/* unlock the device */
up (&dev->sem);
return retval;
}
/**
* skel_ioctl
*/
static int skel_ioctl (struct inode *inode, struct file *file, unsigned int cmd, unsigned long arg)
{
struct usb_skel *dev;
dev = (struct usb_skel *)file->private_data;
/* lock this object */
down (&dev->sem);
/* verify that the device wasn't unplugged */
if (dev->udev == NULL) {
up (&dev->sem);
return -ENODEV;
}
dbg(__FUNCTION__ " - minor %d, cmd 0x%.4x, arg %ld",
dev->minor, cmd, arg);
/* fill in your device specific stuff here */
/* unlock the device */
up (&dev->sem);
/* return that we did not understand this ioctl call */
return -ENOTTY;
}
/**
* skel_write_bulk_callback
*/
static void skel_write_bulk_callback (struct urb *urb)
{
struct usb_skel *dev = (struct usb_skel *)urb->context;
dbg(__FUNCTION__ " - minor %d", dev->minor);
if ((urb->status != -ENOENT) &&
(urb->status != -ECONNRESET)) {
dbg(__FUNCTION__ " - nonzero write bulk status received: %d",
urb->status);
return;
}
return;
}
/**
* skel_probe
*
* Called by the usb core when a new device is connected that it thinks
* this driver might be interested in.
*/
static void * skel_probe(struct usb_device *udev, unsigned int ifnum, const struct usb_device_id *id)
{
struct usb_skel *dev = NULL;
struct usb_interface *interface;
struct usb_interface_descriptor *iface_desc;
struct usb_endpoint_descriptor *endpoint;
int minor;
int buffer_size;
int i;
char name[10];
/* See if the device offered us matches what we can accept */
if ((udev->descriptor.idVendor != USB_SKEL_VENDOR_ID) ||
(udev->descriptor.idProduct != USB_SKEL_PRODUCT_ID)) {
return NULL;
}
/* select a "subminor" number (part of a minor number) */
down (&minor_table_mutex);
for (minor = 0; minor < MAX_DEVICES; ++minor) {
if (minor_table[minor] == NULL)
break;
}
if (minor >= MAX_DEVICES) {
info ("Too many devices plugged in, can not handle this device.");
goto exit;
}
/* allocate memory for our device state and intialize it */
dev = kmalloc (sizeof(struct usb_skel), GFP_KERNEL);
if (dev == NULL) {
err ("Out of memory");
goto exit;
}
minor_table[minor] = dev;
interface = &udev->actconfig->interface[ifnum];
init_MUTEX (&dev->sem);
dev->udev = udev;
dev->interface = interface;
dev->minor = minor;
/* set up the endpoint information */
/* check out the endpoints */
iface_desc = &interface->altsetting[0];
for (i = 0; i < iface_desc->bNumEndpoints; ++i) {
endpoint = &iface_desc->endpoint[i];
if ((endpoint->bEndpointAddress & 0x80) &&
((endpoint->bmAttributes & 3) == 0x02)) {
/* we found a bulk in endpoint */
buffer_size = endpoint->wMaxPacketSize;
dev->bulk_in_size = buffer_size;
dev->bulk_in_endpointAddr = endpoint->bEndpointAddress;
dev->bulk_in_buffer = kmalloc (buffer_size, GFP_KERNEL);
if (!dev->bulk_in_buffer) {
err("Couldn't allocate bulk_in_buffer");
goto error;
}
}
if (((endpoint->bEndpointAddress & 0x80) == 0x00) &&
((endpoint->bmAttributes & 3) == 0x02)) {
/* we found a bulk out endpoint */
dev->write_urb = usb_alloc_urb(0);
if (!dev->write_urb) {
err("No free urbs available");
goto error;
}
buffer_size = endpoint->wMaxPacketSize;
dev->bulk_out_size = buffer_size;
dev->bulk_out_endpointAddr = endpoint->bEndpointAddress;
dev->bulk_out_buffer = kmalloc (buffer_size, GFP_KERNEL);
if (!dev->bulk_out_buffer) {
err("Couldn't allocate bulk_out_buffer");
goto error;
}
FILL_BULK_URB(dev->write_urb, udev,
usb_sndbulkpipe(udev,
endpoint->bEndpointAddress),
dev->bulk_out_buffer, buffer_size,
skel_write_bulk_callback, dev);
}
}
/* initialize the devfs node for this device and register it */
sprintf(name, "skel%d", dev->minor);
dev->devfs = devfs_register (usb_devfs_handle, name,
DEVFS_FL_DEFAULT, USB_MAJOR,
USB_SKEL_MINOR_BASE + dev->minor,
S_IFCHR | S_IRUSR | S_IWUSR |
S_IRGRP | S_IWGRP | S_IROTH,
&skel_fops, NULL);
/* let the user know what node this device is now attached to */
info ("USB Skeleton device now attached to USBSkel%d", dev->minor);
goto exit;
error:
skel_delete (dev);
dev = NULL;
exit:
up (&minor_table_mutex);
return dev;
}
/**
* skel_disconnect
*
* Called by the usb core when the device is removed from the system.
*/
static void skel_disconnect(struct usb_device *udev, void *ptr)
{
struct usb_skel *dev;
int minor;
dev = (struct usb_skel *)ptr;
down (&minor_table_mutex);
down (&dev->sem);
minor = dev->minor;
/* remove our devfs node */
devfs_unregister(dev->devfs);
/* if the device is not opened, then we clean up right now */
if (!dev->open_count) {
up (&dev->sem);
skel_delete (dev);
} else {
dev->udev = NULL;
up (&dev->sem);
}
info("USB Skeleton #%d now disconnected", minor);
up (&minor_table_mutex);
}
/**
* usb_skel_init
*/
static int __init usb_skel_init(void)
{
int result;
/* register this driver with the USB subsystem */
result = usb_register(&skel_driver);
if (result < 0) {
err("usb_register failed for the "__FILE__" driver. Error number %d",
result);
return -1;
}
info(DRIVER_DESC " " DRIVER_VERSION);
return 0;
}
/**
* usb_skel_exit
*/
static void __exit usb_skel_exit(void)
{
/* deregister this driver with the USB subsystem */
usb_deregister(&skel_driver);
}
module_init (usb_skel_init);
module_exit (usb_skel_exit);
MODULE_AUTHOR(DRIVER_AUTHOR);
MODULE_DESCRIPTION(DRIVER_DESC);
MODULE_LICENSE("GPL");
|